Caught in the Spider's Web
by babyvfan
Summary: He should have walked away the second he realized he was in too deep. Cut the strings right from the beginning. Yet he didn't. He couldn't. She was the spider and he the fly. *a Sebastian x Izzy story, loosely based on recent episodes*


**For the ever-witty, forever-sassy LittleNightDragon. Ash, hope you love gift #2 as much as you did gift #1**

* * *

 **Caught in the Spider's Web**

 _One neutral memory that wasn't entirely awful from his pitiful excuse of a childhood happened when he was seven._

 _He was banished to his room, forced to listen to the insufferable shrieking of his "brother" over the's boy dead falcon that went on and on throughout the night. Even with hands and pillows covering his ears, he could still hear that pitiful crying._

 _He cast his eyes over to the room as a way to keep him distracted and calm instead of marching over there and silencing that crying himself. It was there by his window his eyes spotted a fly crawling across the window frame with a spider waiting patiently by the corner of her web. The fly was hypnotized by the silvery threads of the web, the sheer beauty of the spider's creation. The fly's body trembled, almost as if he were trying to resist._

 _But in the end, seductive beauty trumped over common sense. The bug fluttered its wings and flew over to the web._

 _The second the bug had settled in, the spider pounced._

 _Watching that brought to mind every single lesson Valentine had bashed into his head. Always be the puppeteer, never the puppet. The predator, not the pretty. Destroy any and all weaknesses that could destroy you first._

 _Which Sebastian took in stride. It was what made him different from his brother. What made him different. What made him_ better _._

 _Years later he'd find something that became his tempting web, his seductive spider._

 _~...~_

Sebastian was familiar with the Lightwoods, of course. Anyone and everyone involved in the supernatural world were familiar with the name. Powerful, both famous and infamous as the Herondales, the Morgensterns. And the recent lot added more pages to the already impressive family tree. Alec Lightwood, the eldest who was devoted to every whim and rule of the Clave-until he decided to be with a warlock. Max, the youngest who fancied himself a genius. And Isabelle, the only daughter to Robert and Mayrse Lightwood, who shared her mother's dark beauty but was fueled by fire as opposed to her mother's ice.

The first time he met Isabelle face-to-face was during his father's failed invasion at the New York Institute. He knew right from the beginning it was a failure, but it didn't stop him from coming over to watch the mayhem unfold for his own amusement.

His father's failure was his own gain. He managed to get the sword, left carelessly behind by his sister who forgo everything to care for the great Jace Wayland. And he had the chance to meet this interesting Lightwood girl.

On the rooftop he spotted Aldertree and the Lightwood boy being surrounded by Circle Members. The brother opened his mouth to lay out a plan. The sister arrived before it was formed, cutting down the members like paper, moving in a flash of black and silver.

Burning brightly as a flame before dying too soon, collapsing into her brother's arms.

 _A shame_ , Sebastian thought. _She was quite fascinating to watch_. As he walked away with the word, his mind went back to that fascinating flame.

Weeks later he was given a chance to see how lovely she was up close.

He caught word of a Shadowhunter in need of yin-fen. Based on the description one of his sources passed on, the dark curtain of hair, nearly pitch-black eyes, he knew it was her. Which meant he finally found an in inside the Institute, to his dear family.

He scaled the rooftops as she stumbled through the alleys, her voice cracking into weak pleas as she banged against the door of the abandoned vamp den. An easy prey that caught not only his eye but that of a greater demon who wasted no time trapping the fly.

She managed to surprise them both by defending instead of surrendering. Her aim was off, her high kicks shaky, but she pried herself free from the demon's clutches.

Which marked his cue to go, speeding over to them, cutting the demon with a single swing.

As he pulled himself back up, he saw that the rumors of her beauty were true. Even with her skin flushed and sweaty from the effects of withdrawal, her dark hair matted, her wide eyes unfocused, there was no denying the traces of beauty that were doubtlessly mesmerizing.

"Who are you?" she asked.

"I'm a Shadowhunter."

She held the wall like a crutch, her eyes wide and innocent as a doe. For a spilt moment, he wondered if the fascination he witnessed days ago was a fluke. If it was the yin-fen that gave her the power to become that burning flame?

"My name is Sebastian."

Bit by bit, inch by inch, she peeled herself away from the wall, her eyes locked on his. So innocent yet so…captivating, lack for a better word. Captivating. A type of brown only several shades from being pitch-black.

"Isabelle," she finally said.

He should have taken her back to the Institute after that. The act alone would have gained clearance, most definitely praise from the Shadowhunters. Sebastian knew by the look on Isabelle's face, he gained an ally that would be of great use to him. A pawn that would set the steps of his plan into motion.

Instead he brought her back to his apartment.

The way he saw it, it better suited his plan. The more helpful he was to her, the more trust she'd give out to him. So he let her rest until she was better, gave her medicine that speeded up her recovery, and provided food with a story.

The conversation switched over from light to grave as the topic was shone on difficult mothers. During his story, some bits of his own frustrations and anger towards Jocelyn Fairchild slipped into the tale. Her eyes changed with the mood of the story, morphing from delightful to serious-serious and understanding.

It was a sight he didn't anticipate anymore than the feeling that came with it, erupting inside him. Heated, swift, and sharp like a dagger.

So sudden, so foreign he didn't know what to make of it-that look or the feeling that look caused. Despite himself, he dwelled on it too long. Much too long that he slipped, the hellfire burning from his palms, searing through his skin, boiling the tea until the kettle was shrieking.

"I think the tea's ready," she joked.

"Yeah," But he wasn't. It took forever to compose himself, to grasp onto control and rein it in tight. He turned around and shot her a charming smile. "You want some milk? Honey?"

The glow of her smile, the light in her eyes, grew brighter. The strange feeling returned, much sharper.

* * *

The Institute was just as he expected. Everything from the machines, the rooms, the computers, the weapons, and the people. Flocks of brainless sheep. Her inner circle didn't fail his expectations either.

His brother, the great Jace Wayland, all grown-up and still woefully ignorant. Alec Lightwood, the parabatai and brother who Sebastian could already tell was going to be a problem by the frown on his face and suspicion swirling in his eyes as Isabelle recounted her story of being saved. And then his own sister, his flesh and blood, Clarissa.

She was practially the spitting of their mother, although her hair was much lighter, her looks and dwarf size more fitting for a child. The girl who was the bane of his father's existence, the girl he pictured ruling beside him as queen.

Yet he felt nothing. Her touch did nothing to him as their hands shook. It was almost painful to keep the charming smile on his face. What was worse, though, was the fact she barely held his attention. During their brief conversation, his eyes kept going back to Isabelle and her brother.

"Sebastian Verlac shows up out of the blue and saves you?" Suspicion rang high in his voice.

Isabelle frowned at him, but didn't back up, standing tall. "What are you trying to say?"

Her brother said nothing. She said plenty, assuring him that he was on their side, that he just wanted to help.

It was fascinating what her words did to him then, causing that strange, sharp feeling to not only return but to grow, flaring the insides of his stomach. Even if Alec's suspicions were in fact correct.

* * *

His plan was both thriving and withering. Thriving due to the fact that he already spotted countless holes within the Institute, within the people, and planted his seeds. The fact he already had powerful allies, key players that would push his plans forward. Doubt became to spread through the building over Alec Lightwood's leadership skills. The Seelie Queen was at his beck and call, eager to please him. However, as successful as planning was going, it was withering due to the two obstacles.

One was his sister. He expected a warrior, much like the one Valentine often said their mother was. Fierce, cunning. Instead what he found was a child, a silly and reckless child playing warrior.

What was the worse was the fact everything he expected her to be, all the traits he valued and envisioned for his partner, he saw more and more in another girl, which brought on number two: Isabelle Lightwood.

The pawn that was meant to be a means to an end. The one who provoked those strange, damning feelings.

For two solid weeks, he managed to keep his distance, using all the time and energy to continue his planning until he came across her in the training room. Swinging, punching, kicking.

He should have stayed away, pretend he saw nothing and turn the other direction, and yet his feet drew him over to her like a magnet.

"Blowing off some stream?" he joked.

"My mom's in town," she grunted, throwing in several punches to the dummy's abdomen.

His mind went back to their earlier conversation when they first met on difficult mothers, him opening up and her looking at him with those understanding eyes. This time she talked and he listened, watching how the words settled onto her like a thick cloak, weighting down heavily on her.

The sight was infuriating as well as baffling, and hardly anything swayed it. Not his opinion on her strength nor his advice on overcoming struggle. The confident warrior he had gotten to know these couple of days reduced to a defeated child. He didn't like it. He didn't like it one bit. So he did the only thing that would change it.

He threw a punch.

And was flipped onto his back in a heartbeat.

"I am," he said in regards to her skills.

A beam was her reply, and he braced himself for the foreign feeling that slashed through his chest like duel blades.

Later on that night, during the party/meeting Alec Lightwood held as a way to mend the tension between the Shadowhunters and Downwolders, Sebastian finally admitted himself a fact he had been trying not to dwell on: despite planning, despite effort, despite everything, Isabelle Lightwood started to come something to him.

His seductive little spider he couldn't stay away from.

He refused to associate the feeling with need, or anything else relating to that. He was, however, willing to claim on her.

A claim he wanted to stake right then and there as he watched the vampire leader stay close by her throughout most of the night, smiling at her, touching her. Who actually had the nerve to try to intimidate him when he noticed how closely Sebastian had been watching them, watching her.

"Like a predator," he said.

The vampire's only saving grace was the fact the words Sebastian planted on his head, of the corruption he brought into Isabelle's life, how he was the persona of what she was trying to overcome, did just what he wanted. They repelled him, causing him to turn away from her in the end.

It was satisfying to see and should have been the end of it for him. He should have walked away.

Instead Sebastian waited a second or two before he appeared by her side, watching the vampire make his way out. "It's probably for the best."

Isabelle watched the vamp until he was through the doors and gone from sight. Her eyes were wet with tears, but not a single drop fell. She sucked in a deep breath and turned over to Sebastian, eyes clear. A testament to her strength that never ceased to amaze him.

"Maybe," was all she said before she retreated to her room.

* * *

When Aline came to the Institute, paying them all a surprise visit, he was sure that his cover was blown. He was good, brilliant even, but even he had his limits. After all, it was hard to explain half of a year's disappearance when he mentioned he only just left London to clear his addiction. There was also a matter of questions on what he had been doing during that time: the wheres, the whens, and the whos.

Thankfully darling Isabelle was his aid, speaking of his progress, his part in her own recovery, filling in the empty gaps.

He wrangled information from his "twin". He managed to charm Aline. The Seelie Queen managed to create tension between his sister and her boy toys. And Isabelle was such fantastic help. That night, he cooked her dinner in his apartment and then prepared something special as a reward for her help. A triple chocolate mousse cheesecake that made her eyes glow in delight as he passed along a generous slice.

"Is there seriously anything you can't do?" she asked.

"No."

She raised a playful eyebrow. "Cocky much?"

"Very."

She dissolved into laughter and he couldn't fight down the smile that tugged on his mouth. One bite into the dessert and she was transfixed, eyes closed, head tilted back.

"Oh…my…god." she breathed. "This is amazing." Her eyes shone as she they looked over him as she took in another bite. "Let me guess. Right after the soup chef, you traded secrets with a baker."

"Something like that." he smiled. Secrets, money, etc. And in exchange, the baker died a quick, less painful death.

Isabelle took another, bigger bite of the dessert, smearing some of the chocolate sauce onto her cheek. She reached over to wipe it off, but in an instant, Sebastian's hand was on her cheek, this thumb wiping the chocolate away.

He didn't anticipate her skin being so soft. Just as he didn't expect her eyes to darken right then when she looked at him. Those damned eyes that were too big, too brown, too deep, too soft.

Soft like her skin. Soft like the falcon Valentine snapped without a second thought. Soft like his brother who spent the entire night weeping over it. Soft, the exact opposite of everything he was and stood for.

"Sebastian."

His mind went back to the fly and spider he watched so many years ago in his room. How the fly crept closer to the web. How it studied the beautiful web, the beautiful, oblivious to the danger it was being pulled into.

He studied the beautiful spider. Her curtain of sleek, raven hair. Her soft brown eyes. Her red plump lips.

" _To love is to destroy and to be loved is to be destroyed."_ A lesson Valentine bashed into both their skulls from the time they could talk.

His brother was a cautionary tale of it. His sister a weak slave to it.

He should have taken back his hand. He should have laid out distance between them to clear the fog that was clouding his mind.

Instead he closed the distance between them and kissed her, his body shuddering from the intoxicating taste that spilled into his mouth, surging through his veins. He crashed his lips harder against her, causing her to open her mouth more, granting him access to that beautiful ecstasy she held, taking every morsel of it he could have.

She melted into his arms, answering his intensity with her own. Just as hungry, just as desperate.

He pulled her closer and closer, until they were chest to chest, their lips locked in an intense, ravenous hold. Without breaking that hold, he carried her back to the bedroom. He laid her down on the bed. She wrapped her legs around his torso, pulling him closer. The two dissolved into a mess of hands and lips, shed clothes and bare skin.

Hours later, after thorough, exhilarating fun, Isabelle slowly wiggled herself from his hold. She sat upon the bed and brushed loose strands away from his eyes he kept closed for just a bit longer.

When she crept to the end of the bed and began to collect her discarded clothes, he wrapped his arms around her waist and pulled her back in.

"Oh no you don't!"

"Sebastian!" she cried, half shrieking, half laughing.

He laid her flat on the bed and climbed on top of her, straddling her hips, pinning her wrists against her head.

"I'm not done with you yet." he replied with a wolfish grin.

Isabelle giggled as she tried to free herself from him but then her protests turned to moans, to mewls, to pleasurable cries and screams as he had his way with her once more.

* * *

Sebastian wasn't a fool to believe that contentment lasted forever. It hardly did. The predator eventually had the prey after they toyed with them. Demeter took back her daughter, the queen of the underworld. Helen and Paris's affair came to a messy end. For every moment of bliss, there was a gray cloud moving in, building and building until it finally struck, ruining everything.

Still, he wanted to remain in his blissful paradise for a while longer. In Isabelle's lips, her soft skin, her delicious body. But his dark cloud eventually stormed in, in the form of one miss Clarissa Fairchild.

For the most part, he and Isabelle managed to keep things casual between them. During the day they went about their business, keeping things cordial when they crossed paths. Behind closed doors, they indulged, they devoured and ended the night back in his apartment, entangled in between the sheets and each other.

One afternoon, they were sparring in the training room. The action was innocent enough as he pulled Isabelle back on her feet after her high kick turned into his shoulder toss, his hands lingered around her waist a bit too long.

A detail that Clarissa quickly caught on when she came in, eyes narrowing.

"I couldn't help but notice that you've been spending a lot of time downstairs with Valentine," she said after Isabelle left. "Almost as much time as you've been spending with Izzy."

His left brow rose high as he wiped beads of sweat off his face.

"Log-in details show you've been down by his cell almost every day this past week, with footage showing you standing across from the cell and staring at him. Almost like you're planning something." Arms folded against her chest as she walked over to him. "And then when you're up here, your eyes always follow Izzy. Like she's a key to that plan."

"I assume there's a point that will hopefully be made soon."

"Izzy is one of my best friends, Sebastian. She was one of the first people to welcome me here. She's part of my family and I protect my family. She actually vouched for you when Alec wasn't sure about your motivations. For your sake," She looked him directly in the eye. "I hope she's right and there won't be a problem. Otherwise I'll take of it. Permanently."

There was nothing quite like watching a baby kitten trying to act like an lion. It was almost amusing in a sad sort of way. Sebastian cocked his head to the side as he examined her from head to toe. It was mortifying to think there was once a time he wanted to be rule beside him. "You are, in fact, your mother's daughter, Clary. Lovely to look at, remarkable in art. And also so incredibly arrogant. Incredibly meddlesome, inferring in matters that don't concern you. Unbearably, painfully insufferable. And so pitifully, unbelievably way over your head because you believe a few strokes with the stele and a devoted puppet make you invincible."

His poor sister tried to stand her ground, to remain unfazed, but he spotted the cracks. The trembling of her lips, the tears filling her eyes, the clenching and unclenching of her fists. But he still wasn't satisfied. Not yet. He wanted to make one more strike.

"Now, if we're done here," Pasting on his best smile, he leaned in and said, "Why don't you run off and be a good little girl and let the adults handle their own business."

He knew from the way her face crumbled, his words hit the mark. Despite the blow they delivered, Clarissa's own words stuck with him for the rest of the day, into the night. Along, with that infuriating look she had that irritated his skin like a flea.

His irritation only settled as his fingers brushed over the column of Isabelle's neck while she laid beside him, her bare body wrapped around the sheets.

It would be all too easy for him to snap her delicate neck. Rid forever himself of the strange feelings she brought out in him. And the devil knew he could do it, and make it look like an accident to throw suspicion off him.

He could have done it. He should have done it. Yet his fingers continued to stroke her neck, threading his fingers through her hair.

A fly content in his web with her spider.

A beep went on beside him, rattling the nightstand. He reached for the phone, seeing a new message came in.

 _ **I'll do it.**_

Sebastian didn't expect anything less. He knew he had the fool the second he proposed his offer. However…

His eyes went back to Isabelle.

The fly already made himself at home.

Decision made, he replied back to the message: _**I'll need you to pick something else for me...**_ His fingers flew over the keyboard, clicking send.

"How long have you been up?"

Sebastian put down the phone to see Isabelle was now awake, stretching out her long limbs like a cat. She sat up in the bed, wrapping the blanket around her naked chest, flipping her dark curls over one side. "Awhile."

She began to return his smile, but then faltered when she studied his face, her eyes growing troubled. "Are you okay?"

"Not quite," he answered truthfully. "I will be. With a little of this." He closed the gap between them and dropped one, two, three kisses on her lips, feeling her melt. "And a bit of this." He pried the blanket away from her hands and let it fell, unveiling that beautiful body already imprinted with his marks. "And," he said with a purr as he cupped one breast, his thumb playing with the sensitive nipple. "Most definitely this." His other hand crept inside her, stroking her folds.

She trembled with a gasp, falling back into bed as she became undone.

* * *

A month later, Sebastian settled into his new home. It wasn't as fancy or high-tech as the New York Institute or nice as his apartment but it certainly had its perks. Like the fact it was completely cloaked and well-hidden from any detection thanks to charms, spells, and runes the Seelie Queen and his father's old books supplied. It was located in Italy, one of his favorite places in the world, with a magnificent, towering house that was built for a king. It featured a basement that was converted to a dungeon that was armed with so many shiny toys.

And the fact he was given a housewarming gift shortly after he settled in.

Delivered by a generous Shadowhunter who came in with Valentine bound and gagged in one hand and Isabelle Lightwood in the other.

Isabelle wrangled herself free from the captor's hold, throwing him a dirty look as she rubbed her wrist. Shock carved onto her face as she glanced around the room, then deepened to betrayal as she looked forward and met his eyes.

 _No_ , those soft browns screamed. _Yes_ , he smiled back.

"I did as you asked." The Shadowhunter said, interrupting their conversation. "And brought them both here. Now please let my family go."

Sebastian was forced to peel his eyes away from hers to address his little helper. "Thank you, Duncan," he smiled as he cupped his cheek. "You did uphold your end of the bargain."

When he released his cheek, he thrust a sword straight into his back.

" _No!_ " she gasped.

"But I'm afraid I cannot uphold mine."

He tossed the body aside and came closer to his guests, one eyeing him with puzzlement and mistrust, the other in shock and fear.

It was a look, he realized, he didn't like that much on her either. Particularly if he was the cause behind it. Then again he supposed he couldn't really blame her either.

"Why?" she asked, a single word to millions of questions.

Why was he doing this? Why was Valentine here? Why was _she_ here? He decided to answer the easiest ones.

"Him," He jerked his head towards Valentine. "For quality father-son time that's long overdue. As for you," His smile brightened as he took another step closer to her. "I decided that I wanted to keep my darling spider."

Isabelle took a step back. Sebastian brought her forward with a firm grip on her chin, forcing her to meet his eyes.

"Besides," he stroked her cheek. "Every king needs a queen."


End file.
